An on-vehicle device operation apparatus has conventionally been known that uses an operation part arranged near a driver, for example, a steering switch, to execute an operation for an on-vehicle device such as a car audio device or a car air-conditioner (see Japanese Laid-open Patent Publication No. 2013-006472).
However, there has been room for further improvement in a conventional on-vehicle device operation apparatus in that operability thereof is improved.
For example, when a user pushes a switch with no assigned operation among a plurality of operation switches provided in an operation part of a conventional on-vehicle device operation apparatus, the user could not distinguish between failing to push an operation switch and an on-vehicle device being unresponsive and might be confused thereby.